I recently programmed some choirs for a big game composer and I had the liberty of writing the lyrics also--the focus of having a choir was to sound epic, to have that large human sound, and not really to sing a specific song.

What is important, however, is creating a lyric that makes people believe they are singing an actual song instead of just random syllables. So song structure is still important to retain, absolutely, and because they're not real words, you can use sounds that compliment the music or note at the time.

I have listened to Jason's tracks, I believe that the words are fake words, but that he uses certain sound-a-like words to reference something as if in an older/ancient language (ie: Gloria).

It's worth noting that Russell Brower is the composer for WOW now, not Jason anymore sadly. However, I imagine he works with words/syllables in much the same way - sometimes latin-based derivatives, but not any actual language.

It's worth noting that Russell Brower is the composer for WOW now, not Jason anymore sadly. However, I imagine he works with words/syllables in much the same way - sometimes latin-based derivatives, but not any actual language.

Yes he does. There's an audio interview of him at the BlizzCon on the azeroth.fr podcast, episode #28 (end of episode, last 20 mins, interview in english)